A database of National Weather Service rawinsonde (RAOB) data spanning the years 1972-1990 was used to develop an inferred cloud climatology of the continental United States. Surface data collocated and coincident with the RAOB observations were used initially to identify skycover greater than one tenth. A relative humidity-based (with respect to water or ice, depending on temperature) method was then applied to the RAOB database to infer where cloud layers were likely. Cloud top and base temperatures and heights for multiple layers for November through March were compiled.
Results of this inferred cloud climatology are presented and interpreted in terms of aviation weather applications. The extracted cloud information is especially pertinent to in-flight icing and low ceilings. The data were stratified by geographic location, month, latitude, and surface altitude to highlight regions particularly susceptible to these hazards. The information may also be useful to weigh aviation weather forecasts more toward local cloud climatology as prediction time increases.
The 8th Conference on Aviation, Range, and Aerospace Meteorology